learn about the different types of lens and their applications
describe the effect of a thin converging lens on a beam of light
understand technical terms used in converging lens, such as focal length, principal axis and focal point.
Activity 1—A closer look.
Get a Singapore Dollar (any value)
2. Find the smallest word/sentence on the dollar by using just your eyes. 3. Now try using a magnifying glass and look carefully. Did you find it? 4. How did the magnifying glass help you? Discuss and comment below.
1. You are given a set of magnifying glass. 2. Now, move the magnifying glass towards/away such that you can project a focused image on a blank paper 3. Describe the image you see in terms of size and orientation. Suggest another use of the lens of the magnifying glass. Comment below.
The applet simulates the image seen through a lens as you shift the position of object (arrow).
Set the applet as shown in your worksheet.
The curvature radius determines the focal length of the lens. In this case, it is 0.70 m( 70 cm).
Describe the size and orientation of the images as the pencil is placed at the positions indicated in the table below. Do this by circling the correct description below.
Describe the size and orientation of the images as the pencil is placed at the positions indicated in the table below. Do this by circling the correct description below- Do this on your worksheet.
Position of object from center of lens/cm
Size of image compared to object
Orientation of image compared to object
Position of image
50
Enlarged/ Diminished/Same size
Upright/inverted
Same size as object/ Opposite side of lens
60
Enlarged/ Diminished/Same size
Upright/inverted
Same size as object / Opposite side of lens
80
Enlarged/ Diminished/Same size
Upright/inverted
Same size as object / Opposite side of lens
100
Enlarged/ Diminished/Same size
Upright/inverted
Same size as object / Opposite side of lens
140
Enlarged/ Diminished/Same size
Upright/inverted
Same size as object / Opposite side of lens
180
Enlarged/ Diminished/Same size
Upright/inverted
Same size as object / Opposite side of lens
7. Discuss the changes in the images in the table above. Find out the differences and similarities. Suggest the range of position for the changes to happen.
Lesson Objectives
In this lesson you will:
Activity 1—A closer look.
2. Find the smallest word/sentence on the dollar by using just your eyes.
3. Now try using a magnifying glass and look carefully. Did you find it?
4. How did the magnifying glass help you? Discuss and comment below.
COOL STUFF:
*Check out other look security features of the Singapore Currency @
http://www.mas.gov.sg/Currency/Security-Features/How-to-identify-genuine-notes.aspx
Activity 2- Far Far Away Lens
1. You are given a set of magnifying glass.
2. Now, move the magnifying glass towards/away such that you can project a focused image on a blank paper
3. Describe the image you see in terms of size and orientation. Suggest another use of the lens of the magnifying
glass. Comment below.
Activity 3- Far Far Away Lens
Click to play the applet below.
or go to
http://phet.colorado.edu/en/simulation/geometric-optics
The applet simulates the image seen through a lens as you shift the position of object (arrow).
range of position for the changes to happen.